Intake of whole grains has substantial health benefits, which are attributed to various functional substances in whole grains. When consumed, whole grais are digested and fermented in the gastrointestinal tract, transforming active ingredients into important metabolites regulating human health and having multiple beneficial effects on certain human diseases. Numerous studies have shown that diabetes, obesity, inflammatory bowel disease and intestinal cancer are related to diet and the intestinal microflora. Although the relationship between these diseases and whole grains and the gut microbiota has not been thoroughly studied, the interactions between the gut microbiota and whole grains and the effects on the expression of related regulatory genes have been increasingly studied in recent years, and an increasing number of findings have confirmed the role of whole grains in regulating human diseases. In this paper, we review the role and molecular mechanism of whole grains in the regulation of these diseases, which will provide a biological basis and reference for further research and application of whole grains.

The volatile flavor substances of rice with remained germ roasted to different degrees were analyzed and compared by gas chromatography-ion mobility spectrometry (GC-IMS) combined with principal component analysis (PCA), with the aim of establishing fingerprints of volatile components of rice with different roasting degrees. The results showed that the volatile substances of rice samples with different roasting levels could be well separated by GC-IMS, and in total 61 flavor compounds were detected in four rice samples at all roasting stages. Aldehydes, esters and heterocyclic compounds contributed more to the characteristic flavor of roasted rice, while alcohols and ketones also contributed to the characteristic aroma components of roasted rice. The types and contents of aroma compounds of rice with different roasting degrees were significantly different. PCA showed that the GC-IMS spectra of volatile components differed among rice with different roasting degrees, and the cumulative contribution rates of the first two principal components were both 94%, indicating that the flavor fingerprints of rice samples at different roasting levels can be successfully established using GC-IMS.